Fire — it is one of the first technological advancements made by early humans, but it nearly destroyed one of humanity's greatest achievements, the Mir Space Station. In 1997, a fire aboard Mir endangered the lives of the crew and could have ended the decade-long effort and collaboration between Russia, Japan, the United States, and 10 other countries.

Fire in Space
A space station is likely the last place you would want an out of control fire to occur. Unfortunately, such an event happened in February of 1997, with the six Mir crew members left to put the flames out using three on-board fire extinguishers. The fire started, ironically, due to a malfunction in one of the station's life support systems.

Ideally, fire looks different in space — it forms a gas-lined sphere. The fire aboard Mir, however, created a close quarters blowtorch due to the constant oxygen supply released from a faulty oxygen canister.

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How Did the Fire Start?
Switching out oxygen canisters on Mir became a routine, thanks to the number of additional crew members the station often played home to and the multinational nature of the space station. At the time of the fire, a United States and a German astronaut had recently joined the four-man Russian crew aboard Mir.

Mir crew members typically obtained oxygen on Mir through solar-powered electrolysis of water, along with oxygen stored in pressurized oxygen storage tanks.

However, whenever the space station became home to more than three crew members, additional oxygen supply became necessary. To increase the breathable air supply, the astronauts used chemical oxygen canisters — the culprit in the Mir fire.

Each canister supplied one day's worth of oxygen for a single crew member, with thousands of canisters used during the lifetime of Mir.

Just prior to the February 1997 fire, an unknown event occurred during the replacement process, causing one of the canisters to ignite shortly after replacement. The flames had a sufficient oxygen supply due to a chemical reaction going on within the canister, leading to a blade of flame that threatened the lives of the crew and singed the interior of one of the Mir capsules.

Crew members took turns using extinguishers to put out the fire, with at least one astronaut needed to hold the user in place so that they did not move backward in the absence of gravity. The threat of the fire was two-fold, with the possibility of personal burns and the destruction of a capsule wall possible, an event that would likely have killed the entire crew.

What Is In a Chemical Oxygen Canister?

The oxygen canisters used aboard Mir worked by a rather simple, but efficient, chemical reaction. The canisters contained solid lithium perchlorate. Heating the solid gave off gas phase oxygen, leaving the rather inert solid lithium chloride behind.

In the process, a large amount of oxygen is given off, released over time into the Mir capsules to provide breathable air.

What Led to the Fire?
It is currently believed that a small piece of glove became lodged in the replacement container. A series of experiments conducted in the years following the Mir fire determined that if a piece of latex glove becomes stuck in a chemical oxygen generator, it can initiate a fire similar to the one observed in 1997 aboard Mir.

This discovery led to an alteration of protocol when changing out the generators, with the latex gloves used in the process aboard stations now collected and examined for defects after installation is completed.

A large time discrepancy exists regarding the duration of the fire. Newly arrived U.S. astronaut and physician Dr. Jerry Linenger stated the fire lasted a painful 14 minutes. The fire occurred in Linenger's second month on Mir, with Dr. Linenger describing the flame as a "raging blowtorch."

Linenger also noted that Russian officials downplayed both the extent and duration of the fire, contending that the fire lasted nearly 15 minutes instead of the 90 seconds professed by early NASA and Russian Federal Space Agency reports.

While you may never find yourself aboard a space station, if you fly, you come in contact with inactive chemical oxygen generators. Chemical oxygen generators are placed aboard commercial aircraft, ready to supply oxygen in case of a drop in cabin pressure. The oxygen will stream through the plastic masks dangling in front of your face, but hopefully, you will never need to use one.

The top image is of the Mir Space Station as viewed by the Shuttle Endeavor in January of 1998. Image via NASA. Additional image of Mir after the fire courtesy of NASA.Sources linked within.Avoid fires while aboard spacecraft.